In hilly terrain where roads run downhill and/or uphill, some vehicles travel much more slowly than others. Such is for example the case in mountainous areas where heavy trucks have to negotiate major upgrades or downgrades. This may entail the driver of such a vehicle manually activating warning flashers to make drivers of other vehicles aware that his/her vehicle is travelling at a relatively low speed. However, such activation of warning flashers may be sporadic and inconsistent. Some drivers of vehicles travelling markedly more slowly than other traffic may for example forget or not bother to activate/deactivate warning flashers in such situations.
A known practice is to provide cars with functionality for automatically activating warning flashers when the vehicle becomes involved in various kinds of accident, e.g. a collision with another vehicle or a fixed object.
Another known practice is to provide heavy vehicles in particular with functionality for automatically activating warning flashers when the vehicle is subjected to sharp braking and is thereby relatively quickly retarded relative to surrounding traffic.
U.S. Pat. No. 7,057,501 describes a method for automatic activation of warning flashers when it is detected that a vehicle behind is relatively close.